76 lines
1.1 KiB
C++
76 lines
1.1 KiB
C++
#ifndef __DEMO_H__
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#define __DEMO_H__
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// 抽象状态类
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class State
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{
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public:
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// 声明抽象方法
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virtual void handle() = 0;
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};
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// 具体状态类
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class ConcreteState :public State
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{
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public:
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// 实现
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void handle(){
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// ……
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}
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};
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// 上下文类
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class Context
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{
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public:
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// set方法设置状态对象
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void setState(State* iState){
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this->state = iState;
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}
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// 对外封装的方法
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void request(){
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// do something
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state->handle();
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}
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private:
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// 引用状态对象
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State *state;
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};
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// 1.由环境类来决定实例化为哪一个具体状态类对象
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class Context
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{
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public:
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void convertState(){
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if (condition1){
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this->state = new ConcreteStateA();
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}
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else if (condition2){
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this->state = new ConcreteStateB();
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}
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else{
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// do something
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}
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}
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private:
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// 引用状态对象
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State *state;
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};
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// 2.有具体状态类来决定转换成哪一个具体状态类对象
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class ConcreteState :public State
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{
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public:
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void convertState(Context* ctx){
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if (condition1){
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ctx->setState(new ConcreteStateA());
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}
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else if (condition2){
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ctx->setState(new ConcreteStateB());
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}
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else{
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// do something
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}
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}
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};
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#endif //__DEMO_H__
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